Suction cap for ink-jet recording apparatus

ABSTRACT

The invention includes a suction cap that does not retain ink therein. The suction cap includes a cap member having a recess and a suction opening formed therein and a capillary force generating member disposed in the recess. When a recovery operation is performed for ink ejection using the suction cap, ink sucked from a nozzle flows downwardly from a tilt surface of the recess due to gravity and a suction force applied through the suction opening. The ink impinges a side face of a projection of the capillary force generating member, flowing into defined narrow spaces, due to the action of capillary force of the ink, and flowing toward the suction opening. The ink in the defined narrow spaces is discharged by the suction force applied through the suction opening to outside the suction cap.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to an ink-jet recording apparatus that performsrecording by ejecting an ink droplet, and more particularly, to theink-jet recording apparatus that has a recovery mechanism for inkejection.

2. Description of Related Art

A known recording apparatus, such as a printer, that performs printingon a recording medium, such as a sheet of paper and an overheadtransparency film, includes a print head of, for example, an ink-jettype, a dot impact type, or a thermal transfer type. Specially, theink-jet print head performs high-speed and high-quality printing with alow noise level, without having complicated structures.

In the ink-jet head, a plurality of nozzles that eject ink are formed.In order to perform high-quality printing using the ink-jet print head,ink in and around the nozzles needs to be maintained in appropriateconditions. More specifically, when the ink is placed in inappropriateconditions where, for example, the ink contains air bubbles or dirt orother contaminants, or is dried and becomes viscous due to evaporationof the ink solvent, the ink may not be ejected or may be inappropriatelyejected. In such cases, a recovery operation to obtain proper inkejection is performed to clear the inappropriate conditions of the inkor to eliminate the causes of the ink ejection failure.

In order to perform the recovery operation, some ink-jet recordingapparatuses include a cap that covers an ejection surface of the ink-jetprint head where openings of the nozzles are provided, a suction pumpthat sucks ink from the ink-jet print head through a tube connected tothe cap, by applying a suction force to the cap, and a waste inkreservoir that receives ink sucked by the suction pump. The suction pumpis driven when the cap covers the nozzle ejection surface, to generate anegative pressure in the cap, thereby forcibly discharging ink from theink-jet print head. Thus, causes of the ink ejection failure areeliminated.

The ink received in the cap by the recovery operation is required to becompletely discharged from the cap, through the suction pump, to thewaste ink reservoir, by the application of the suction force. However,the ink may not be discharged completely from the cap, but may remain inthe cap, due to the structure of the cap.

If the ink remains in the cap, the ink may leak into the ink-jetprinter, or solidify in the cap or on the edges, which prevents the capfrom covering the ejection surface tightly. If the cap is used to coverthe ejection surface when recording is not performed, the ink remainingin the cap may be attached to the ejection surface when the cap coversthe ejection surface. Such an attachment of ink to the ejection surfacecauses, for example, the ink to be ejected in a direction shifted orvaried from a predetermined direction, resulting in an ink ejectionfailure.

To solve the above-described problems, an ink-jet recording apparatus isdisclosed in Japanese Patent No. 2806611. In Japanese Patent No.2806611, the cap has a 0.4 mm to 0.7 mm-wide groove at a bottom wall ofa recess of a cap which defines a space or room with the print headejection surface when the cap covers the ejection surface. The ink iscollected in the groove and the collected ink is discharged from the capthrough a suction opening formed in the bottom wall of the recess.

However, when the cap having the groove at the bottom wall of the recessthereof is formed by molding, the groove is required to have a certainwidth, to prevent a mold for the cap from breaking where the groove isformed. Accordingly, a cap having a narrow groove is difficult to formby molding. Therefore, the groove is, in reality, formed with anunnarrow, or wide, width. However, the groove with a wide width does notlead the ink in the cap completely to the suction opening, so that theink is likely to remain in the cap. If the cap is formed by cutting,manufacturing processes for the cap become complicated, resulting in anincrease in cost so as to become impractical.

SUMMARY OF THE INVENTION

To solve the above-described drawbacks, the invention provides anink-jet recording apparatus including a cap that is formed with a simplestructure and does not leave ink in the cap.

An ink-jet recording apparatus according to the invention may include arecording head including an ejection surface and at least one nozzleformed thereon for recording onto a recording medium by ejecting inkfrom the nozzle, a cap device for covering the ejection surface of therecording head, and a suction device connected to the suction openingformed in the recess of the cap device and able to suck the ink throughthe nozzle and discharge the sucked ink from the cap device through asuction opening.

The cap device may include a cap member and a capillary force generatingmember. The cap member includes a contact portion able to be in contactwith the ejection surface and a recess forming a room with the ejectionsurface of the recording head when the cap member contacts the ejectionsurface of the recording head, the suction opening communicating withthe recess through which ink is sucked. The capillary force generatingmember may be separately formed from the cap member. The capillary forcegenerating member may be disposed in the cap member to form spaces witha inner surface of the recess of the cap member so that capillary forceis generated toward a part of the inner surface of the recess where thesuction opening is formed.

In the ink-jet recording apparatus having the above-described structure,as the suction device sucks the ink from the nozzles when the cap memberof the cap device contacts the ejection surface of the recording head,the ink is received in the recess of the cap member. By disposing thecapillary force generating member in the recess, spaces are formedbetween the capillary force generating member and the inner surface ofthe recess. In the spaces a capillary force is generated toward a partof the inner surface of the recess where the suction opening is formed.Therefore, the ink in the recess can be discharged smoothly outside thecap device, through the suction opening, without being left in therecess, by a suction force applied by the suction device.

Because the ink does not remain in the cap device, problems such thatthe ink-jet printing apparatus is contaminated with the ink remaining inthe cap device or the occurrence of an ink ejection failure can beprevented. Therefore, an ink-jet recording apparatus that maintains highprint quality can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention will be described in detail withreference to the following figures wherein:

FIG. 1 is a perspective view of a color ink-jet printer of an ink-jetrecording apparatus according to an exemplary embodiment of theinvention;

FIG. 2 is a perspective view of a suction cap;

FIG. 3 is a sectional view of the suction cap, taken along a lengththereof,

FIG. 4 is a sectional view of the suction cap, taken along a line 4—4 inFIG. 3;

FIG. 5 is an explanatory view of the suction cap and an ink-jet printhead facing each other;

FIG. 6 is a perspective view of a capillary force generating memberaccording to a first embodiment;

FIG. 7 is a perspective view of a capillary force generating memberaccording to a second embodiment;

FIG. 8 is a sectional view of a capillary force generating memberaccording to a third embodiment;

FIG. 9 is a sectional view of the suction cap, taken along a lengththereof; and

FIG. 10 is a sectional view of the suction cap, taken along a line 10—10in FIG. 9.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Exemplary embodiments of the invention will be described in detail withreference to the figures.

Referring to FIG. 1, the configuration of an ink-jet printer 21 as anink-jet recording apparatus will be described below. As shown in FIG. 1,the ink-jet printer 21 includes ink cartridges 22, ink-jet print heads24, a carriage 26, a drive unit 27, a platen roller 28, and a purgedevice 29. Each ink cartridge 22, as an ink supply member, contains oneof yellow, magenta, cyan and black ink. The ink-jet print heads 24, asrecording heads, perform printing onto a paper sheet 23, for example, asa recording medium. The carriage 26, as a supporting member, supportsthe ink cartridges 22 and the ink-jet print heads 24 mounted thereon.The drive unit 27 linearly reciprocates the carriage 26. The platenroller 28 extends in the direction the carriage 26 reciprocates, and isdisposed opposite to the ink-jet print heads 24.

The drive unit 27 includes a carriage shaft 30, a guide plate 31,pulleys 32, 33 and an endless belt 34. The carriage shaft 30 is providedat a lower end portion of the carriage 26 and extends parallel to theplaten roller 28. The guide plate 31 is provided at an upper portion ofthe carriage 26 and extends parallel to the carriage shaft 30. Thepulleys 32, 33 are disposed between the carriage shaft 30 and the guideplate 31, at each end portion of the carriage shaft 30. The endless belt34 is placed over the pulleys 32, 33.

Provided at a lower portion of the carriage 26 is a carriage shaftsupporting portion 35 into which the carriage shaft 30 is inserted. Atan upper portion of the carriage 26, a guide plate contact portion 36 isprovided where the guide plate 31 contacts thereto. The endless belt 34is connected to a rear surface of the carriage 26.

When the pulley 32 is rotated by a motor 32A in a forward or reversedirection, the carriage 26, to which the endless belt 34 is connected,is linearly reciprocated along the carriage shaft 30 and the guide plate31, in the direction of the width of the paper sheet 23.

The paper sheet 23 is fed from a sheet cassette(not shown) provided inthe ink-jet printer 21. The paper sheet 23 is fed between an ejectionsurface 24 a of the ink-jet print heads 24, facing downwardly withrespect to the vertical direction, and the platen roller 28. Printing isconducted by ejecting ink from the nozzles of the ink-jet print heads24. Thereafter, the paper sheet 23 is discharged. Paper feeding anddischarging mechanisms are omitted in FIG. 1.

The purge device 29 is provided to a side of the platen roller 28. Thepurge device 29 is arranged so as to face the ejection surface 24 a whena print head unit 25 is in a reset position (in the forward position inFIG. 1 provided in the main scanning direction outwardly of an end of aprinting area). The purge device 29 is used to clear an ink ejectionfailure, such as when air bubbles or dirt or other containments aretrapped in the nozzles, or the ink dries and becomes viscous due to theevaporation of ink solvent. The purge device 29 includes a suction cap41, as a cap member, that covers the nozzles of the ink-jet print heads24, a suction pump 38 and a cam 39, as a suction device, and a waste inkreservoir 40.

When the print head unit 25 is in the reset position, the cam 39 isdriven by a motor (not shown), to cover the ejection surface 24 a of aprint head 24 with the suction cap 41, and then to forcibly dischargethe ink, in the print head 24, containing air bubbles or dirt that causethe ink ejection failure, from the nozzles using the suction pump 38, bya purge operation. Therefore, the ink-jet print head 24 is brought intorecovery. Thus, the recovery operation for ink ejection is performed toprevent the ink ejection failure from being caused due to clogged ink orthe air bubbles produced at the time when the ink is first introducedinto the print head 24. The sucked ink, which is likely to cause the inkejection failure, is received and stored in the waste ink reservoir 40.

In the embodiments, the suction cap 41 has a size to cover the nozzlesof one print head for one color at a time. When the purge operation isperformed for the nozzles for more than one color, a series ofoperations, of covering the ejection surface 24 a with the suction cap41 and sucking the ink using the suction pump 38, is performed for thenozzles for each of the colors. In this example, four operations areperformed to clean the nozzles of each of the four colors. The carriage26 is constructed to be moved in the main scanning direction to coverthe ejection surface 24 a for a desired color, when necessary.

Provided to a side of the suction cap 41 are protective caps 37 thatcover all nozzles of each color at one time. When the print head unit 25is in a stop position (in the forward end position provided in the mainscanning direction, i.e., right end of carriage shaft 30, as shown inFIG. 1), the protective caps 37 cover the ejection surfaces 24 a of theink-jet print heads 24 for all colors.

As shown in FIGS. 2 through 5, the suction cap 41 includes a cap member42 and a capillary force generating member 50. The cap member 42 has arecess 43 that forms a room with the ejection surface 24 a of the printhead 24 when the suction cap 41 contacts the surface 24 a. The capillaryforce generating member 50 is disposed in the recess 43 of the capmember 42. The cap member 42 is formed of an elastic material, forexample, butyl-rubber. The cap member 42 has a contact portion 45 whichcontacts the ejection surface 24 a. The recess 43 extends in the samedirection as a row of nozzles of the ink-jet print heads 24. The nozzlerow is not illustrated in the drawings. However, the nozzle row isprovided, in a manner similar to the known ink-jet print heads, in thedirection orthogonal to the reciprocating movement directions of thecarriage 26. The recess 43 includes a first recessed portion 43 alocated on the side of ejection surface 24 a when the cap member 42faces the ejection surface 24 a, a second recessed portion 43 bcontinuous with the first recessed portion 43 a and located on the sideof the first recessed portion 43 a opposite to the ejection surface 24a, and a suction opening 44 formed at a bottom 46 of the second recessedportion 43 b.

The first recessed portion 43 a of the recess 43 is contiguous to thecontact portion 45 and provided downwardly from the contact portion 45.The first recessed portion 43 a has tapered inner surfaces (tiltsurfaces 48), gradually becoming narrower toward the second recessedportion 43 b, so as to make the opening area of the first recessedportion 43 a smaller. The second recessed portion 43 b extends in thesame direction as a nozzle row of the ink-jet print heads 24. The secondrecessed portion 43 b is formed like a groove whose one end in thelongitudinal direction is placed lower than the other end, as shown inFIGS. 3 and 5. The suction opening 44 is formed on a lowest end portionof the bottom 46 of the second recessed portion 43 b, with respect tothe vertical direction.

Formed at the lower parts of the inner surfaces (tilt surfaces 48) ofthe first recessed portion 43 a are protrusions 47 that protrude so asto narrow the upper opening portion of the second recessed portion 43 b.The protrusions 47 are deformable due to the elasticity of the rubbermaterial.

As shown in FIG. 5, the suction opening 44 is connected to the suctionpump 38, through a tube 60. The suction pump 38 is connected to thewaste ink reservoir 40 (shown in FIG. 1), through a tube 61.

The capillary force generating member 50 is formed of resin material,for example, polyacetal resin, by molding. As shown in FIG. 6, thecapillary force generating member 50 is integrally formed with aplate-like base 51 and a projection 52 provided at a top surface 54 ofthe base 51. The width of the projection 52 is smaller than the width ofthe base 51. The length of the projection 52 is approximately the sameas the length of the base 51 and the height of the projection has adownward slope toward the end adjacent the suction opening 44. As shownin FIG. 4, the outline of the capillary force generating member 50 is asubstantially an upside down “T” letter shape. The width of the base 51is longer than the distance between the protrusions 47,47 and slightlysmaller than the distance between side inner surfaces 49 of the secondrecessed portion 43 b. The height of the base 51 between the top surface54 and a bottom surface 55 is shorter than the distance between thebottom 46 of the second recessed portion 43 b and the protrusion 47.Each end portion of the top surface 54 of the base 51 in the directionof the width thereof serves as an engagement portion 53 that engageswith a protrusion 47 of the recess 43.

To set the capillary force generating member 50 into the recess 43 ofthe cap member 42, while facing the bottom surface 55 of the base 51 ofthe capillary force generating member 50 toward the bottom 46 of thesecond recessed portion 43 b, the base 51 is inserted through theopening of the first recessed portion 43 a toward the bottom 46. Thebase 51 is disposed between the side inner surfaces 49 below theprotrusions 47 by deforming the protrusions 47. Thus, the capillaryforce generating member 50 is set into the second recessed portion 43 bof the cap member 42.

In the state where the capillary force generating member 50 is set intothe second recessed portion 43 b, a top face 56 of the projection 52 ofthe capillary force generating member 50 is disposed above theprotrusions 47 of the recess 43 (toward the opening of the firstrecessed portion 43 a), as shown in FIG. 4. Further, as shown in FIG. 3,an end of the capillary force generating member 50 in the direction ofthe length thereof partially covers the suction opening 44 on the sideof the second recessed portion 43 b. The movement of the capillary forcegenerating member 50 in the longitudinal directions is regulated, withan end 59 thereof, by a regulating surface 65 extending from the sideinner surfaces 49 of the second recessed portion 43 b. Therefore, thesuction opening 44 on the side of the recess 43 is not completely butpartially covered with the capillary force generating member 50.

As shown in FIG. 4, a space A is formed by the protrusion 47 of therecess 43, a side face 57 of the projection 52, and the top surface 54of the base 51 of the capillary force generating member 50. In the spaceA, the distance between the protrusion 47 of the recess 43 and the sideface 57 of the projection 52 is approximately 0.1 mm to 0.3 mm. When thedistance between the protrusion 47 and the side face falls within therange of 0.1 mm to 0.3 mm, ink was not left in the recess 43. Inaddition to the space A, a very small space B is formed between the sideinner surface 49 of the second recessed portion 43 b and a side surface58 of the base 51. The space B is, for example, 0.05 mm and narrowerthan the space between the protrusion 47 and the side face 57. Thecapillary force generating member 50 is inserted into the secondrecessed portion 43 b of the cap member 42 but not attached thereto.Therefore, a fine space C is formed between the bottom surface 55 of thebase 51 and the bottom 46 of the second recessed portion 43 b. Capillaryforce is generated, due to the spaces A, B, and C, toward the bottom 46of the second recessed portion 43 b where the suction opening 44 isformed.

The recovery operation for ink ejection using the suction cap 41structured as described above will be described. When the print headunit 25 is in the reset position, the cam 39 is driven by a motor (notshown) to cover the ejection surface 24 a of a print head 24 with thesuction cap 41 by contacting the contact portion 45 of the suction cap41 to the ejection surface 24 a, thereby forming a room defined by theejection surface 24 a and the recess 43. Then, a negative pressure isproduced in the enclosed room using the suction pump 38 driven by thecam 39, to suck the ink from the ink-jet print head 24 through thenozzles. The sucked ink is discharged into the waste ink reservoir 40.

Thereafter, the contact portion 45 of the suction cap 41 is separatedfrom the ejection surface 24 a of the ink-jet print head 24, by drivingthe cam 39. In this state, the suction pump 38 is further driven todischarge the ink in the recess 43 of the suction cap 41 outside the cap41, through the suction opening 44. At this time, the ink on the tiltsurface 48 of the recess 43 flows downwardly due to gravity and thesuction force applied through the suction opening 44. The ink impingeson the side face 57 of the projection 52 of the capillary forcegenerating member 50, flowing into the space A. The ink flows from thespace A to the spaces B and C, and then toward the suction opening 44 bythe capillary action of the ink. The ink in the spaces B and C isdischarged from the suction cap 41, through the suction opening 44, bythe application of the suction force.

As described above, the suction cap 41 has the capillary forcegenerating member 50 disposed in the second recessed portion 43 b, whichis formed separately from the cap member 42, having the recess 43 andthe suction opening 44, thereby forming the small spaces A, B, and C.The capillary force is generated toward the bottom 46 where the suctionopening 44 is formed. Therefore, the ink received by the recess 43 ofthe cap member 42 is led to the bottom 46 of the recess 43, where thesuction opening 44 is formed, by the capillary force generated in thespace A, as well as the spaces B and C, which are smaller than the spaceA. The ink is discharged outside the suction cap 41, without leavingbehind ink in the recess 43, by the suction force applied through thesuction opening 44.

The capillary force generating member 50 and the cap member 42 arereadily formed by molding. In addition, because the capillary forcegenerating member 50 is only inserted into the second recessed portion43 b of the cap member 42, the manufacturing process for the suction cap41 is not complicated.

The protrusions 47 of the recess 43 of the cap member 42 prevent thecapillary force generating member 50, which is disposed in the recess 43by simply inserting the member 50 into the recess 43, from coming outfrom the second recessed portion 43 b. Because the capillary forcegenerating member 50 is not attached to the recess 43, a very smallspace C is formed between the bottom surface 55 of the base 51 and thebottom 46 of the recess 43. The capillary force generated in the verysmall space C attracts the ink in the vicinity of the space C, to thespace C. Consequently, the ink in the recess 43 is discharged smoothly,without leaving behind ink in the recess 43, outside the suction cap 41by the suction force applied through the suction hole 44.

The ink on the tilt surface 48 of the first recessed portion 43 a flowsdownwardly due to gravity and the suction force applied through thesuction opening 44. Then, the ink impinges the side face 57 of theprojection 52 of the capillary force generating member 50, flowing intothe space A, which is formed by the protrusion 47 of the recess 43, thetop surface 54 (the engagement portion 53) of the base 51, and the sideface 57 of the projection 52, because the top face 56 of the projection52 of the capillary force generating member 50 is disposed above theprotrusions 47 of the recess 43. The ink flowing into the space A isthen led to the spaces B and C by the capillary force generated therein.The ink in the spaces B and C is subjected to the suction force appliedby the suction pump 38. Therefore, the ink is discharged from thesuction cap 41 through the suction opening 44, by the application of thesuction force, without leaving behind ink on the capillary forcegenerating member 50.

The suction force by the suction pump 38 is reliably applied to the inkin the spaces B and C through the suction opening 44, by covering a partof the suction opening 44 on the side of the second recessed portion 43b. The ink in the recess 43 is discharged, by the suction force appliedby the suction pump 38, outside the suction cap 41, through the spaces Band C, and the suction opening 44.

When the capillary force generating member 50 was, for example,sandblasted or coated with an elastomer to have a better wettabilitythan the inner surface of the recess 43, the ink in the recess 43 couldbe discharged smoothly, through the suction opening 44, outside thesuction cap 41 without leaving the ink in the recess 43, with asynergism with the capillary force generated in the spaces A, B, and C.Similar results were obtained even when corners of the second recessedportion 43 b and the capillary force generating member 50 were not sharpor the top face 56 of the capillary force generating member 50 wassubstantially flat.

Because the ejection surfaces 24 a of the ink-jet print heads 24 facedownwardly with respect to the vertical direction and the suctionopening 44 is formed on the lowest end portion of the tilted bottom 46of the second recessed portion 43 b, with respect to the verticaldirection, the ink sucked from the nozzles of the ink-jet print head 24,in the direction of gravity and received in the recess 43, is led to thesuction opening 44 due to gravity. The ink in the recess 43 isdischarged, outside the suction cap 41 by the suction force appliedthrough the suction opening 44, without leaving ink in the recess 43.

As shown in FIG. 7, the capillary force generating member 50 accordingto a second embodiment has a plurality of grooves 70 that extend in thelongitudinal direction of the projection 52. The width of the grooves 70becomes narrower as the grooves 70 come closer to the suction opening44. With this structure, the ink on the projection 52 is led toward thesuction opening 44 by the capillary force generated in the grooves 70.Thus, the ink in the recess 43 is reliably discharged through thesuction opening 44 outside the suction cap 41, by the application of thesuction force, without leaving behind ink in the recess 43.

As shown in FIG. 8, the capillary force generating member 50 accordingto a third embodiment has a generally triangular or convex cross sectionorthogonal to the longitudinal direction of the projection 52. Theprojection 52 has a tilt surface 52 b extending from a top thereoftoward the space A. The surfaces of the capillary force generatingmember 50 are coated with a high water-repellent film 50 a, such as afluoric film or a silicone film. Alternatively, the capillary forcegenerating member 50 may be formed of a resin material having a highwater repellency, such as fluoroplastics and silicone resin. Thestructure renders the surface of the capillary force generating member50 repellent to ink, causing the ink to quickly flow down along the tiltsurface 52 b into the space A. The ink in the space A flows by thecapillary force, generated in the spaces B and C, between the secondpart 43 b and the capillary force generating member 50.

When an upper portion of the projection 52 is flat or the angle of thetilt surface 52 b is not sharp, the ink may stay on the upper portion ofthe projection 52 even if the ink becomes drop like due to the waterrepellency of the capillary force generating member 50. In view of this,the capillary force generating member 50 having a high wettability, suchas the above-described capillary force generating member 50, may bepreferred. However, if the tilt surface 52 b is provided at an anglegreater than a predetermined amount, the ink flows and is smoothlydischarged with synergistic effects of water-repellency of the capillaryforce generating member 50 and the tilt angle of the tilt surface 52 b.The capillary force generating member 50 may be tilted or angled withrespect to the direction of a length thereof, as shown in FIG. 3. Thetilt angle F, which is indicated in FIG. 3, is preferably about fivedegrees or greater, with respect to the level surface. The tilt angle Fhas a first component in the slope of the bottom 46 and a secondcomponent in the slope of the top of the projection 52. It is preferablethat the tilt be provided on the capillary force generating member 50 inthe widthwise direction thereof, orthogonal to the longitudinaldirection of the projection 52, as shown in FIG. 8, because the greatertilt angle may be provided.

As shown in FIGS. 9 and 10, the projection 52 of the capillary forcegenerating member 50 according to a fourth embodiment, is formed of anink absorbable material, such as porous material having fluid absorbingproperties. For the ink absorbable material, polyurethane foam or afelt-like fiber layers may be used. In this case, a hole 50 b is formedin the capillary force generating member 50 so as to face to the suctionopening 44, as shown in FIG. 10. The ink absorbed by the projection 52is discharged through the hole 50 b. With this structure, the ink in therecess 43 frothing immediately after the purge operation is performed,is absorbed by the projection 52 of the capillary force generatingmember 50 that has fluid absorbing properties. The absorbed ink isdischarged from the recess 43, through the hole 50 b and the suctionopening 44, so that the occurrence of the frothing ink in the recess 43is prevented or reduced. Further, the ink is prevented by capillarityfrom being left in the recess 43.

In the above described embodiments, the suction cap 41 is used only tosuck ink. However, the suction cap may be used to suck ink and protectthe print heads 24. The suction cap 41 in the above-describedembodiments has a size for covering the nozzles for only one color at atime. However, the suction cap 41 may have such a size that it coversthe nozzles of a plurality of print heads 24 for a plurality of colorsat one time. Further, a plurality of the suction caps 41, each suctioncap 41 covering the nozzles for a different color, may be provided and,correspondingly, a plurality of the suction pumps 38 may be provided,one for each of the suction caps 41.

While the invention has been described with reference to theembodiments, it is to be understood that the invention is not restrictedto the particular forms shown in the foregoing embodiments. Variousmodifications and alterations can be made thereto without departing fromthe scope of the invention, as set forth in the appended claims.

For example, the suction cap 41 adapted for the ink-jet print heads 24that eject a plurality of colors of ink are employed in theabove-described embodiments. However, the suction cap 41 adapted for anink-jet print head that ejects one color of ink may be used.

In the above-described embodiments, the ejection surface 24 a of theink-jet print head 24 faces downwardly. However, the ejection surface 24a may face toward a downward slanting direction or toward a side (in thehorizontal direction). The latter case, or a downward slanting directionwould require the lower end of the suction cap to be a flat surface orto have a downward slope toward the opening relative to the horizontalsurface on which the ink-jet recording apparatus is replaced.

What is claimed is:
 1. An ink-jet recording apparatus, comprising: arecording head including an ejection surface and at least one nozzleformed thereon for recording onto a recording medium by ejecting inkfrom the nozzle; a cap device for covering the ejection surface of therecording head, the cap device including: a cap member including acontact portion able to be in contact with the ejection surface and arecess forming a room with the ejection surface of the recording headwhen the cap member contacts to the ejection surface of the recordinghead, and a suction opening communicating with the recess through whichink is sucked; and a capillary force generating member separately formedfrom the cap member, the capillary force generating member disposed inthe cap member to form spaces with an inner surface of the recess of thecap member so that a capillary force is generated toward a part of theinner surface of the recess where the suction opening is formed; and asuction device connected to the suction opening of the cap member forsucking the ink of the recording head through the nozzle and dischargingthe sucked ink from the cap device through the suction opening.
 2. Theink-jet recording apparatus according to claim 1, wherein the recess ofthe cap member comprises a first recessed portion located contiguouslyto the contact portion, and a second recessed portion continuous withthe first recessed portion and located opposite the contact portion withrespect to the first recessed portion, the second recessed portionhaving disposed therein the capillary force generating member with thespaces, and the second recessed portion communicates with the suctionopening.
 3. The ink-jet recording apparatus according to claim 2,wherein the cap member includes an elastically-deformable protrusionthat protrudes from the inner surface thereof so as to narrow thecontinuous portion between the first recessed portion and secondrecessed portion, and the capillary force generating member is heldbetween the protrusion and a bottom face of the second recessed portion.4. The ink-jet recording apparatus according to claim 3, wherein thecapillary force generating member includes a projection that projectsinto the first recessed portion beyond the protrusion of the cap member,and the protrusion and the projection of the capillary force generatingmember define one of the spaces.
 5. The ink-jet recording apparatusaccording to claim 4, wherein the other of the spaces between thecapillary force generating member and the inner surface of the secondrecessed portion is smaller than the one of the spaces between theprojection and the protrusion.
 6. The ink-jet recording apparatusaccording to claim 4, wherein the projection of the capillary forcegenerating member includes, on a side thereof facing the first recessedportion, at least one groove whose width becomes smaller as the at leastone groove approaches the suction opening.
 7. The ink-jet recordingapparatus according to claim 4, wherein the projection of the capillaryforce generating member includes a tilt surface that is provided at suchan angle that a droplet of the ink moves by an own weight thereof, thetilt surface having a water repellency.
 8. The ink-jet recordingapparatus according to claim 7, wherein the tilt surface of theprojection of the capillary force generating member is directed towardthe one of the spaces formed by the projection and the protrusion. 9.The ink-jet recording apparatus according to claim 4, wherein at least apart of the projection of the capillary force generating member isformed of a porous material having a fluid absorbing property.
 10. Theink-jet recording apparatus according to claim 9, wherein the capillaryforce generating member includes an opening provided beneath theprojection that communicates with the suction opening through thecapillary force generating member.
 11. The ink-jet recording apparatusaccording to claim 2, wherein the first recessed portion consists oftapered faces gradually becoming narrower toward the second recessedportion.
 12. The ink-jet recording apparatus according to claim 2,wherein a part of the inner surface of the second recessed portion wherethe suction opening is formed is tilted toward the suction opening. 13.The ink-jet recording apparatus according to claim 1, wherein thecapillary force generating member is disposed so as to partially coverthe suction opening on the side of the recess.
 14. The ink-jet recordingapparatus according to claim 1, wherein the recording head includes aplurality of nozzles aligned in a row, the capillary force generatingmember extends in a same direction as the row.
 15. The ink-jet recordingapparatus according to claim 1, wherein the capillary force generatingmember has a better wettability than the inner surface of the recess.16. The ink-jet recording apparatus according to claim 15, wherein thecapillary force generating member includes a surface sandblasted orcoated with elastomer to have a high wettability.
 17. The ink-jetrecording apparatus according to claim 1, wherein the suction opening isformed at a lowest position with respect to a vertical direction, in thepart of the inner surface of the recess facing the ejection surface ofthe recording head when the cap member contacts the ejection surface ofthe recording head.
 18. The ink-jet recording apparatus according toclaim 17, wherein the ejection surface of the recording head facesdownward with respect to the vertical direction, and the part of theinner surface of the recess is tilted toward the suction opening.
 19. Acap for use with an ink-ejection recovery device to oppose an ejectionsurface of a print apparatus, the cap comprising: a cap member having: afirst axis; a second axis transverse to the first axis; a perimeterwall, an upper surface of the perimeter wall forming a contact lip forengaging the ejection of the cap surface; a base having an opening atone end of the first axis proximate the perimeter wall; and a protrusionextending from an inner surface of the perimeter wall at least alongeach portion of the perimeter wall extending along the first axis; and acapillary force generating member mounted in the cap member and retainedtherein by the protrusion.
 20. The cap according to claim 19, whereinthe base and the perimeter wall define a recess, the protrusion dividingthe recess into a first recess and a second recess, the capillary forcegenerating member retained in the second recess.
 21. The cap accordingto claim 20, wherein the capillary force generating member has asubstantially upside down T-shape in cross section, a cross bar of theT-shape retained in the second recess and a base leg of the T-shapeextending between the protrusions.
 22. The cap according to claim 21,wherein the base leg has a substantially flat end, the flat endextending beyond the protrusion into the first recess.
 23. The capaccording to claim 22, wherein the substantially flat end has at leastone groove extending along the first axis and narrowing toward an endproximate the opening.
 24. The cap according to claim 22, wherein thecapillary force generating member has a roughened surface to have agreater wettability than a surface of the recess.
 25. The cap accordingto claim 21, wherein the base leg has a substantially triangular orconvex shape in cross section, an apex or peak of the shape extendingbeyond the protrusion into the first recess.
 26. The cap according toclaim 25, wherein surfaces of the capillary force generating member arecoated with a water repellant film.
 27. The cap according to claim 25,wherein the capillary force generating member is made of a waterrepellant material.
 28. The cap according to claim 21, wherein the baseleg is formed of an ink absorbable material and the cross bar has anopening that overlaps, at least in part, the opening in the base. 29.The cap according to claim 20, wherein a depth of the recess at an endof the first axis where the opening is located is greater than a depthof the recess at the other end of the first axis.
 30. The cap accordingto claim 20, further comprising a regulating surface in the secondrecess at an end of the first axis where the opening in the base islocated, the regulating surface preventing the capillary forcegenerating member from completely overlying the opening.
 31. The capaccording to claim 19, wherein an inner surface of the perimeter wallfrom the contact lip to the protrusion is a substantially flat tiltsurface.